sizeof测类型（数组名除外） strlen测实际长度 strncpy返回指针类型

 1 #include <stdio.h>
 2 #include <stdlib.h>
 3 #include <string.h>
 4 int main()
 5 {
 6     char *p="wangddd";
 7     printf("%d\n",sizeof(p));//输出4,指针类型
 8
 9     char x[8];
10     printf("%d\n",sizeof(x));//输出8，所占内存数
11
12     printf("%s\n",strncpy(x,"wangddddd",sizeof(x)));//返回x指针，正常显示前7位
13     //strncpy返回值是一个指针x
14     printf("%d\n",sizeof(strncpy(x,"wangddddd",sizeof(x))));//输出4
15     printf("%d\n",strlen(strncpy(x,"jskjksjdf",sizeof(x))));//随机 取决于编译环境
16     printf("%d\n",strlen(strncpy(x,"jskjkse",sizeof(x))));//输出7
17
18     char y[5]="w c";
19     printf("%d\n",strlen(y));//输出3
20     printf("%d\n",sizeof(y));//输出5
21
22     return 0;
23 }